Correct!
1. CT shows a focal lesion projecting into the right superior mediastinum
Unenhanced thoracic CT shows a low attenuation focus (single arrowhead) projecting into the right superior mediastinum adjacent to the right brachiocephalic vein, accounting for the finding at presentation chest radiography. No pleural abnormality is seen and the great arteries and veins appear normal. Aside from the lesion itself, there are no features to suggest mediastinal lymph node enlargement. The pericardium is normal and no significant fluid collection is seen. In particular, the location of the lesion is too cranial to represent a pericardial recess, even a normal variant pericardial recess, such as the so-called “high-riding” right paratracheal superior pericardial recess. Of note, periosteal reaction involves the right clavicular head (arrow), and prominent asymmetric soft tissue is seen around the right clavicular head as well (double arrowheads).
Which of the following differential diagnostic considerations is least appropriate for the imaging findings in this patient? (Click on the correct answer to proceed to the fifth of seven pages)